Chief Daniel Walden alerted dispatchers as he pushed down on the gas pedal to catch the pickup driver.

"Dispatchers let me know they got a call of a vehicle matching the description dropped off a load of undocumented right in that area that we were at," Walden said as the chase neared the county line.

At that point, the driver ditched the truck and took off on foot, with the officer on his heels.

Five minutes later, they emerged from the brush, the driver in handcuffs.

According to officials, that was just another typical day in Brooks County.

What isn't typical is the deputy making the arrest, Chief Walden. Walden is a school district police officer in Donna, Texas, nearly 80 miles away.

"It's something I took a personal interest in," said Walden. "We're law enforcement. We're not immigration. But we're human beings and we care about someone's life."

Brooks is one of the poorest counties in the nation. With enough funding to employ four deputies, that means only one deputy on duty each day. Brooks County is also home to one of the last border checkpoints into the interior of the United States.

Human smugglers are taking advantage of those facts, dropping off migrants, who are often left to wander and die within the thousands of acres of ranch land.

With more than 40 bodies already recovered this year, one deputy can quickly get overwhelmed.

So Walden, along with more than a dozen other peace officers from across the state, donate their time and their badges to help Brooks County tackle its immigration crisis.

"You take a county the size of Rhode Island and you put one deputy out there by himself, what are you going to do?" said Walden. "We are a brotherhood in law enforcement, which means when an officer needs help, we'll help them."

Deputies say hay bales help hide the undocumented migrants. The water jugs are there to keep them hydrated.(Photo: Joe Conger)

Following the traffic stop, it turned out the driver was undocumented, the truck wasn't his, and he was vague about his travel plans.

The driver will be charged with felony evasion.

Walden named his group the Border Brotherhood, and in less than 3 months, Brooks County 911 response times have improved, along with the survival rates for the undocumented migrants.

County officials admit to being skeptical at first of the volunteers who've padded their ranks. But Brooks County Chief Deputy Bennie Martinez said they have come to accept the reserve deputies and their help.

"They're coming at their own dime, looking for nothing in return," said Martinez "Those are hard to come by. People just don't do things like that anymore."

Austin Malone is from San Antonio. In his free time, he's a volunteer deputy.

"Back in San Antonio I go to school, and have a part time job working security," said Malone. "I don't want people to get lost and die."